1. Field
The disclosed concept relates generally to electrical switching apparatus and, more particularly, to electrical switching apparatus, such as circuit breakers. The disclosed concept also relates to charging assemblies for circuit breakers.
2. Background Information
Electrical switching apparatus, such as circuit breakers, provide protection for electrical systems from electrical fault conditions such as, for example, current overloads, short circuits, abnormal voltage and other fault conditions. Typically, circuit breakers include an operating mechanism, which opens electrical contact assemblies to interrupt the flow of current through the conductors of an electrical system in response to such fault conditions as detected, for example, by a trip unit. The electrical contact assemblies include stationary electrical contacts and corresponding movable electrical contacts that are separable from the stationary electrical contacts.
Among other components, the operating mechanisms of some stored energy circuit breakers, for example, typically include a pole shaft, a trip actuator assembly, a closing assembly and an opening assembly. The trip actuator assembly responds to the trip unit and actuates the operating mechanism. The closing assembly and the opening assembly may have some common elements, which are structured to move the movable electrical contacts between a first, open position, wherein the movable and stationary electrical contacts are separated, and a second, closed position, wherein the movable and stationary electrical contacts are electrically connected.
The closing assembly includes a chargeable stored energy mechanism such as, for example and without limitation, a closing spring, as well as a close latch, a charging handle, and a close button to actuate (e.g., discharge) the closing spring to facilitate the closing process. The charging handle for the closing assemblies of some circuit breakers includes a ratcheting mechanism with a pawl that engages recesses or teeth in a ratchet at the base of the handle in an attempt to resist undesired handle backlash. It is possible, however, for the close latch or other closing assembly components to become damaged, for example, by forces and an associated collision of components resulting from a sudden release of the charging handle during the charging process, before the pawl can stop the backwards rotation.
There is, therefore, room for improvement in electrical switching apparatus, such as circuit breakers, and in charging assemblies therefor.